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Abstract:

A ground working apparatus has a plow assembly including a frame formed
with an attached runner and a plow tool. A linkage assembly couples the
frame to a bridle assembly for movement of the plow assembly between
raised and lowered positions relative to the bridle assembly. The runner
and the plow tool depend downwardly from the frame to concurrently run
over and plow, respectively, ground to be plowed along a plowing path
ahead of the bridle assembly and the plow assembly, wherein the runner
sets the frame of the plow assembly at a fixed elevated position with
respect to the ground to be plow.

Claims:

1. A ground working apparatus, comprising: a bridle assembly to secure a
plow frame; a plow assembly comprises a frame, and a runner and a plow
tool each coupled to the frame; a linkage assembly coupling the frame to
the bridle assembly to secure a plow frame for movement of the plow
assembly between raised and lowered positions relative to the bridle
assembly; and the runner and the plow tool depending downwardly from the
frame to concurrently run over and plow, respectively, ground to be
plowed along a plowing path ahead of the bridle assembly and the plow
assembly, and the runner to run over the ground to be plowed to set the
frame of the plow assembly at a fixed elevated position with respect to
the ground to be plow.

2. A ground working apparatus according to claim 1, further comprising
first means coupled between the bridle assembly and the linkage assembly
applying a bias to the linkage assembly urging the plow assembly toward
the raised position away from the lowered position.

3. A ground working apparatus according to claim 2, further comprising:
the plow tool mounted to the frame for movement between a lowered plowing
position and an elevated clearance position; and second means coupled
between the frame and the plow tool urging the plow tool in a direction
toward the lowered plowing position.

4. A ground working apparatus according to claim 3, wherein the first
means comprises a first compression spring coupled between the bridle
assembly and the linkage assembly.

5. A ground working apparatus according to claim 4, wherein the second
means comprises a second compression spring coupled between the frame and
the plow tool.

6. A ground working apparatus according to claim 3, wherein the runner is
positioned between the plow tool and the bridle assembly.

7. A ground working apparatus according to claim 6, wherein: the plow
tool comprises an elongate shank coupled to the frame and which depends
downwardly therefrom to an attached tilling head assembly to extend into
and plow the ground to be plowed in the lowered plowing position of the
plow tool; and the runner comprises an elongate, rigid support having an
upper end coupled to the frame and which depends downwardly therefrom to
an opposed lower end formed with a ground-engaging skid set forwardly of
and above the tilling head assembly to support the frame at an elevated
position relative to the ground to be plowed by the tilling head
assembly.

8. A ground working apparatus according to claim 7, wherein the linkage
assembly comprises a four-bar linkage pivotally coupled between the frame
and the bridle assembly.

9. A ground working apparatus, comprising: a bridle assembly to secure a
plow frame; a plow assembly comprises a frame, and a runner and a plow
tool each coupled to the frame; a linkage assembly pivotally coupled
between the frame and the bridle assembly permitting movement of the plow
assembly between raised and lowered positions relative to the bridle
assembly; the runner and the plow tool depending downwardly from the
frame to concurrently run over and plow, respectively, ground to be
plowed along a plowing path ahead of the bridle assembly and the plow
assembly, and the runner to run over the ground to be plowed to set the
frame of the plow assembly at a fixed elevated position with respect to
the ground to be plow; the linkage assembly comprises generally
horizontal upper and lower links pivoted to the frame and the bridle at
frame and bridle pivot points, respectively; an extension of the lower
link extends forwardly of the bridle pivot point of the lower link away
from the plow assembly; and first means coupled between the bridle
assembly and the extension of the lower link applying a bias to the lower
link urging the plow assembly toward the raised position away from the
lowered position.

10. A ground working apparatus according to claim 9, further comprising:
the plow tool mounted to the frame for movement between a lowered plowing
position and an elevated clearance position; and second means coupled
between the frame and the plow tool urging the plow tool in a direction
toward the lowered plowing position.

11. A ground working apparatus according to claim 10, wherein the first
means comprises a first compression spring coupled between the bridle
assembly and the extension of the lower link.

12. A ground working apparatus according to claim 11, wherein the first
compression spring has an upper end pivoted to the bridle assembly, and
an opposed lower end pivoted to the extension of the lower link.

13. A ground working apparatus according to claim 12, wherein the second
means comprises a second compression spring coupled between the frame and
the plow tool.

14. A ground working apparatus according to claim 10, wherein the runner
is positioned between the plow tool and the bridle assembly.

15. A ground working apparatus according to claim 14, wherein: the plow
tool comprises an elongate shank coupled to the frame and which depends
downwardly therefrom to an attached tilling head assembly to extend into
and plow the ground to be plowed in the lowered plowing position of the
plow tool; and the runner comprises an elongate, rigid support having an
upper end coupled to the frame and which depends downwardly therefrom to
an opposed lower end formed with a ground-engaging skid set forwardly of
and above the tilling head assembly to support the frame at an elevated
position relative to the ground to be plowed by the tilling head
assembly.

16. A ground working apparatus, comprising: a bridle assembly to secure a
plow frame; a plow assembly comprises a frame, and a runner and a plow
tool each coupled to the frame; a linkage assembly pivotally coupled
between the frame and the bridle assembly permitting the plow assembly to
displace between raised and lowered positions relative to the bridle
assembly; the runner and the plow tool depending downwardly from the
frame to concurrently run over and plow, respectively, ground to be
plowed along a plowing path ahead of the bridle assembly and the plow
assembly, and the runner to run over the ground to be plowed to set the
frame of the plow assembly at a fixed elevated position with respect to
the ground to be plow; the linkage assembly comprises generally
horizontal upper and lower links pivoted to the frame and the bridle at
frame and bridle pivot points, respectively; an extension of the lower
link extending forwardly of the bridle pivot point of the lower link away
from the plow assembly; a bracket affixed to the bridle assembly near the
bridle pivot point of the upper link; and a bridle spring coupled between
the bracket and the extension of the lower link applying a bias to the
lower link at the extension urging the plow assembly toward the raised
position away from the lowered position and the ground to be plowed.

17. A ground working apparatus according to claim 16, wherein the bridle
spring has an upper end pivoted to the bracket, and an opposed lower end
pivoted to the extension of the lower link.

18. A ground working apparatus according to claim 16, wherein the runner
is positioned between the plow tool and the bridle assembly.

19. A ground working apparatus according to claim 18, wherein: the plow
tool comprises an elongate shank coupled to the frame and which depends
downwardly therefrom to an attached tilling head assembly to extend into
and plow the ground to be plowed; and the runner comprises an elongate,
rigid support having an upper end coupled to the frame and which depends
downwardly therefrom to an opposed lower end formed with a
ground-engaging skid set forwardly of and above the tilling head assembly
to support the frame at an elevated position relative to the ground to be
plowed by the tilling head assembly.

20. A ground working apparatus according to claim 19, further comprising:
the shank mounted to the frame for movement between a lowered plowing
position of the tilling head assembly to plow the ground to be plowed and
an elevated clearance position of the tilling head assembly; and a plow
spring coupled between the frame and the shank urging the plow tool in a
direction toward the lowered plowing position of the tilling head
assembly.

Description:

FIELD OF THE INVENTION

[0001] The present invention relates to an agricultural implements used to
plow soil for cultivating purposes.

BACKGROUND OF THE INVENTION

[0002] Modern cultivating tool shanks routinely incorporate automatic plow
shank reset features utilizing springs to apply an initial preset force
resisting movement of the shank upwardly from the plowing or field
working position. The preset force is generated through a predetermined
preload on the reset spring. Once the preset force is overcome, such as
when the plow shank encounters a bolder or other rigid object, the plow
shank displaces upwardly to clear the obstruction compressing the spring.
After the obstruction is cleared, the spring decompresses forcing the
plow shank downwardly back to the plowing or field working position.

[0003] The upward displacement of the plow shank is commonly referred to
as tripping, and the horizontal force required to induce tripping is
commonly referred to as the trip force. Although conventional automatic
shank reset features are beneficial, the plow shank ultimately takes the
full brunt of the trip force, which, notwithstanding plow shank
displacement, often damages the plow shank, which leads to costly and
time-consuming repairs. Furthermore, automatic shank reset features in
prior art plow shanks routinely maintain an irregular or unpredictable
plow depth, particular in hard and dense soil conditions, which often
requires multiple plowing operations to produce the desired soil
preparation.

SUMMARY OF THE INVENTION

[0004] According to the principle of the invention a ground working
apparatus includes a bridle assembly to secure a plow frame, and a plow
assembly. The plow assembly includes a frame, and a runner and a plow
tool each coupled to the frame. A linkage assembly couples the frame to
the bridle assembly to secure a plow frame for movement of the plow
assembly between raised and lowered positions relative to the bridle
assembly. The runner and the plow tool depend downwardly from the frame
to concurrently run over and plow, respectively, ground to be plowed
along a plowing path ahead of the bridle assembly and the plow assembly,
and the runner to run over the ground to be plowed to set the frame of
the plow assembly at a fixed elevated position with respect to the ground
to be plow. A bridle spring is coupled between the bridle assembly and
the linkage assembly, which applies a bias to the linkage assembly urging
the plow assembly toward the raised position away from the lowered
position. The plow tool is mounted to the frame for movement between a
lowered plowing position and an elevated clearance position, and a plow
spring is coupled between the frame and the plow tool urging the plow
tool in a direction toward the lowered plowing position. The runner is
positioned between the plow tool and the bridle assembly. In particular,
the plow tool consists of an elongate shank coupled to the frame and
which depends downwardly therefrom to an attached tilling head assembly
to extend into and plow the ground to be plowed in the lowered plowing
position of the plow tool. The runner includes an elongate, rigid support
having an upper end coupled to the frame and which depends downwardly
therefrom to an opposed lower end formed with a ground-engaging skid set
forwardly of and above the tilling head assembly to support the frame at
an elevated position relative to the ground to be plowed by the tilling
head assembly. The linkage assembly is a four-bar linkage pivotally
coupled between the frame and the bridle assembly.

[0005] According to the principle of the invention, a ground working
apparatus includes a bridle assembly to secure a plow frame, and a plow
assembly. The plow assembly includes a frame, and a runner and a plow
tool each coupled to the frame. A linkage assembly is pivotally coupled
between the frame and the bridle assembly permitting movement of the plow
assembly between raised and lowered positions relative to the bridle
assembly. The runner and the plow tool depend downwardly from the frame
to concurrently run over and plow, respectively, ground to be plowed
along a plowing path ahead of the bridle assembly and the plow assembly,
and the runner to run over the ground to be plowed to set the frame of
the plow assembly at a fixed elevated position with respect to the ground
to be plow. The linkage assembly consists of generally horizontal upper
and lower links pivoted to the frame and the bridle at frame and bridle
pivot points, respectively. An extension of the lower link extends
forwardly of the bridle pivot point of the lower link away from the plow
assembly, and a bridle spring is coupled between the bridle assembly and
the extension of the lower link applying a bias to the lower link urging
the plow assembly toward the raised position away from the lowered
position. The plow tool is mounted to the frame for movement between a
lowered plowing position and an elevated clearance position, and a plow
spring is coupled between the frame and the plow tool urging the plow
tool in a direction toward the lowered plowing position. The bridle
spring has an upper end pivoted to the bridle assembly, and an opposed
lower end pivoted to the extension of the lower link. The runner is
positioned between the plow tool and the bridle assembly. In particular,
the plow tool includes an elongate shank coupled to the frame and which
depends downwardly therefrom to an attached tilling head assembly to
extend into and plow the ground to be plowed in the lowered plowing
position of the plow tool. The runner consists of an elongate, rigid
support having an upper end coupled to the frame and which depends
downwardly therefrom to an opposed lower end formed with a
ground-engaging skid set forwardly of and above the tilling head assembly
to support the frame at an elevated position relative to the ground to be
plowed by the tilling head assembly.

[0006] According to the principle of the invention, a ground working
apparatus includes a bridle assembly to secure a plow frame, and a plow
assembly. The plow assembly includes a frame, and a runner and a plow
tool each coupled to the frame. A linkage assembly is pivotally coupled
between the frame and the bridle assembly permitting the plow assembly to
displace between raised and lowered positions relative to the bridle
assembly. The runner and the plow tool depend downwardly from the frame
to concurrently run over and plow, respectively, ground to be plowed
along a plowing path ahead of the bridle assembly and the plow assembly,
and the runner to run over the ground to be plowed to set the frame of
the plow assembly at a fixed elevated position with respect to the ground
to be plow. The linkage assembly consists of generally horizontal upper
and lower links pivoted to the frame and the bridle at frame and bridle
pivot points, respectively, and there is an extension of the lower link
extending forwardly of the bridle pivot point of the lower link away from
the plow assembly. A bracket is affixed to the bridle assembly near the
bridle pivot point of the upper link, and a bridle spring is coupled
between the bracket and the extension of the lower link applying a bias
to the lower link at the extension urging the plow assembly toward the
raised position away from the lowered position and the ground to be
plowed. The bridle spring has an upper end pivoted to the bracket, and an
opposed lower end pivoted to the extension of the lower link. The runner
is positioned between the plow tool and the bridle assembly. In
particular, the plow tool includes an elongate shank coupled to the frame
and which depends downwardly therefrom to an attached tilling head
assembly to extend into and plow the ground to be plowed. The runner
consists of an elongate, rigid support having an upper end coupled to the
frame and which depends downwardly therefrom to an opposed lower end
formed with a ground-engaging skid set forwardly of and above the tilling
head assembly to support the frame at an elevated position relative to
the ground to be plowed by the tilling head assembly. The shank is
mounted to the frame for movement between a lowered plowing position of
the tilling head assembly to plow the ground to be plowed and an elevated
clearance position of the tilling head assembly, and a plow spring is
coupled between the frame and the shank urging the plow tool in a
direction toward the lowered plowing position of the tilling head
assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Referring to the drawings:

[0008] FIG. 1 is a rear perspective view of a ground working apparatus
constructed and arranged in accordance with the principle of the
invention, the ground working apparatus including a plow assembly, a
bridle assembly to secure a plow frame, and a linkage assembly coupling
the plow assembly to the bridle assembly;

[0009]FIG. 2 is a front perspective view of the ground working apparatus
of FIG. 1;

[0010] FIG. 3 is an exploded perspective view of the ground working
apparatus of FIG. 1;

[0011] FIG. 4 is a right side elevation view of the ground working
apparatus of FIG. 1;

[0012] FIG. 5 is a left side elevation view of the ground working
apparatus of FIG. 4;

[0013] FIG. 6 is a front elevation view of the ground working apparatus of
FIG. 1;

[0014] FIG. 7 is a rear elevation view of the ground working apparatus of
FIG. 1;

[0015] FIG. 8 is an enlarged, fragmented, front elevation view of the
ground working apparatus of FIG. 1 illustrating a bridle spring coupled
between the bridle assembly and the linkage assembly;

[0016] FIG. 9 is an enlarged, fragmented, rear elevation view of the
ground working apparatus of FIG. 1 illustrating a plow spring coupled
between a frame and a plow tool of the plow assembly;

[0017] FIG. 10 is a section view taken along line 10-10 of FIG. 5;

[0018] FIG. 10A is a view similar to that of FIG. 10 illustrating a plow
spring support assembly as it would appear in a raised position
compressing a plow spring coupled between a frame and a plow tool of a
plow assembly;

[0019] FIG. 11 is a side elevation view of the ground working apparatus of
FIG. 1 illustrating the plow assembly as it would appear in a raised
position relative to the bridle assembly; and

[0020] FIG. 12 is a side elevation view of the ground working apparatus of
FIG. 1 illustrating a plow tool of the plow assembly as it would appear
in an elevated clearance position relative to a lowered plowing position
of the plow tool illustrated in phantom outline.

DETAILED DESCRIPTION

§A. Overview of the Ground Working Apparatus

[0021] Turning now to the drawings, in which like reference characters
indicate corresponding elements throughout the several views, attention
is first directed to FIGS. 1 and 2 illustrating a ground working
apparatus 20 constructed and arranged in accordance with the principle of
the invention including a plow assembly 21, a bridle assembly 22 to
secure a plow frame denoted generally at 23, and a linkage assembly 24
coupling plow assembly 21 to bridle assembly 22. Ground working apparatus
20 is stout, strong, robust, and of substantial construction being formed
principally of steel or other strong, resilient metal as is common with
conventional plow assemblies of the type used to plow soil for
cultivating purposes. Throughout the various drawings, only a portion of
plow frame 23 is shown for illustration and reference, which, for
illustrative purposes, consists of a segment 23' an elongate frame member
forming a part of plow frame 23.

[0022] Plow assembly 21 includes a frame 30, and a runner 31 and a plow
tool 32 each coupled directly to frame 30. Linkage assembly 24 couples
frame 30 to bridle assembly 22 to secure a plow frame 23 for movement or
displacement of plow assembly 21 in reciprocal directions relative to
bridle assembly 22 as generally indicated by double arrowed line A in
FIGS. 4, 5 and 11 between a lowered position of plow assembly 21 with
respect to bridle assembly 22 as shown in FIGS. 4 and 5, and a raised
position of plow assembly with respect to bridle assembly 22 as shown in
FIG. 11. Plow assembly 21 is positioned upright behind bridle assembly
22, frame 30 is set at an elevated location relative to ground to be
plowed 26 illustrated in FIG. 4, and runner 31 and plow tool 32 depend
downwardly from frame 30 to concurrently run over and plow, respectively,
ground to be plowed 26 as illustrated in FIG. 4 along a plowing path B
ahead of ground working apparatus 20. Runner 31 is positioned between
plow assembly 21 and bridle assembly 22, and runner 31 runs over ground
to be plowed 26 to set frame 30 of plow assembly 21 at fixed elevated
position with respect to ground to be plowed 26 as ground working
apparatus 20 is moved and applied along plowing path B denoted in FIG. 4
in a direction leading with bridle assembly 22 and trailing with plow
assembly 21.

[0023] A bias is applied between bridle assembly 22 and linkage assembly
24 biasing linkage assembly 24 urging plow assembly 21 toward the raised
position of plow assembly 21 away from the lowered position of plow
assembly 21 partially taking up plow assembly 21. Plow assembly 21 has or
otherwise defines a load, and the bias applied between bridle assembly 22
and linkage assembly 24 takes up some of the load of plow assembly 21
allowing plow assembly 21 to more easily displace upwardly into its
raised position from its lowered position, and dampens movement of plow
assembly 21 from its raised position back to its lowered position
preventing plow assembly from slamming against the ground to be plowed,
which could otherwise damage plow assembly 21 or compromise the linkage
between plow assembly 21 and bridle assembly 22.

[0024] Plow tool 32 is, in turn, mounted to frame 30 for movement in
reciprocal directions as generally indicated by the double arrowed line C
in FIGS. 4 and 12 between a lowered plowing position as shown in FIG. 4
to plow ground to be plowed 26, and an elevated clearance position as
shown in FIG. 12 to clear an impacting obstacle. A bias is applied
between frame 30 and plow tool 32 urging plow tool 32 in a direction
toward the lowered plowing position shown in FIG. 4, and which yet
permits plow tool 32 to displace upwardly during a tripping event,
namely, when plow tool 32 encounters an obstacle.

[0025] Ground working apparatus 20 is an exemplary agricultural implement
used to plow soil for cultivating purposes. Ground working apparatus 20
is normally used with a plurality of such devices which are generally
mounted in a spaced and side-by-side relationship on a plow frame of a
cultivating implement, such as plow frame 23, which is drawn by a
tractor.

[0026] Having presented the general aspects of ground working apparatus
20, the specific structure details of plow assembly 21, bridle assembly
22, and linkage assembly 24 are discussed throughout the remainder of
this specification. It is to be understood that ground working apparatus
20 incorporates numerous conventional nut-and-bolt assemblies each
including a bolt consisting of a shank or shaft having an end formed with
an enlarged bolt head and an opposed externally threaded end, and an
internally threaded nut that threads onto and secures the externally
threaded end. The bolts of the various nut-and-bolt assemblies are
conventionally installed through openings formed in the various parts of
ground working apparatus 20, and are assembled with the corresponding
threaded nuts to secure parts together and to provide pivoting mounts
between various pivoted or pivotally attached parts of ground working
apparatus 20 as will be explained in detail below. The various
nut-and-bolt assemblies and the corresponding openings that receive the
bolts represent conventional arrangements, the use and application of
which are well-known to the skilled artisan. As such, the various
nut-and-bolt assemblies are not discussed in detail and are each given a
general reference numeral for reference purposes, and the various
openings that receive the bolts of the corresponding nut-and-bolt
assemblies are considered part of the nut-and-bolt assemblies and are
thus also referenced by the reference numerals denoting the various
nut-and-bolt assemblies. As such, when a nut-and-bolt assembly is applied
to a structural element, the bolt is received by an opening in the
structural element and is secured between the bolt head and the threaded
nut. Furthermore, when a nut-and-bolt assembly is applied to structural
elements, the bolt is received by corresponding openings in the
structural elements, which are secured between the bolt head located on
one side of one of the structural elements and the threaded nut located
on an opposing side of the opposed structural element.

[0027] Throughout the ensuing specification nut-and-bolt assemblies are
incorporated as various pivotal mounts. Those having regard for the art
will readily appreciate that pivot pins and other forms of pivot mounts
may be used without departing from the invention. Furthermore, at various
points throughout this specification terms such as "substantially,"
"generally," and "approximately" are used to describe characteristics.
Those having regard for the art will readily appreciate that when such
terms are used to describe a characteristic, the described characteristic
is more present than not.

§B. The Plow Assembly

[0028] Plow assembly 21 consists of frame 30, and runner 31 and plow tool
32 each coupled directly to frame 30. Referencing FIGS. 1-3, frame 30
includes opposed upper and lower ends 40 and 41, opposed front and rear
ends 42 and 43, and opposed sides 44 and 45. Sides 44 and 45 are defined
by opposed side plates 50 and 51 extending between upper and lower ends
40 and 41, and opposed front and rear ends 42 and 43. Upper end 40 is
closed by a top plate 52, and front end 42 is closed by a front plate 53,
both of which extend between side plates 50 and 51. Side plates 50 and 51
are open at lower end 41 and rear end 43 of frame 30, and lead to an
interior space or chamber 54 defined by and between side plates 50 and
51, top plate 52, and front plate 53. Side plates 50 and 51 and top and
front plates 52 and 53 are preferably welded together.

[0029] Plow tool 32 is an assembly of substantial construction consisting
of a tough, resilient shank 60 and an attached tilling head or tilling
head assembly 61 designed to plow or till ground to be plowed 26 as shown
in FIG. 4. Looking to FIG. 3, shank 60 is elongate and arcuate and has an
inner or proximal end 64 and an opposed outer or distal end 65. Proximal
end 64 extends into chamber 54 through rear end 43 of frame 30 and is
coupled to frame 30 near or otherwise proximate to front end 42 of frame
30 between upper and lower ends 40 and 41 of frame 30. Shank 60 extends
rearwardly from proximal end 64 through rear end 43 of frame 30, and
further extends rearwardly of rear end 43 of frame 30 and curves and
depends downwardly from frame 30 and then curves inwardly toward rear end
43 of frame 30 to distal end 65 formed with a conventionally-formed
tilling head assembly 61, which is located downwardly of or otherwise
below frame 30 to extend into and plow ground to be plowed in the lowered
plowing position of plow tool 32.

[0030] As mentioned above, plow tool 32 is mounted to frame 30 for
movement in reciprocal directions as generally indicated by the double
arrowed line C in FIGS. 4 and 12 between a lowered plowing position as
shown in FIG. 4 to extend into and plow ground to be plowed 26, and an
elevated clearance position as shown in FIG. 12 to clear an impacting
obstacle. In particular, and with continuing reference to FIG. 3,
proximal end of shank 60 is mounted to frame 30 for pivotal movement with
a nut-and-bolt assembly 67 between the lowered plowing position of plow
tool 32 consisting of a lowered plowing position of tilling head assembly
61 to extend into and plow ground to be plowed 26 as shown in FIG. 4, and
the elevated clearance position of plow tool 32 consisting of an elevated
clearance position of tilling head assembly 61 as shown in FIG. 12, and a
plow spring 70 is coupled between frame 30 and shank 60 of plow tool 32,
which applies the bias between frame 30 and shank 60 of plow tool 32
urging plow tool 32 in the direction toward the lowered plowing position
of plow tool 32 consisting of the lowered plowing position of tilling
head assembly 61 as shown in FIG. 4. Nut-and-bolt assembly 67 is applied
to side plates 50 and 51 of frame near front end 42 of frame 30 between
upper and lower ends 40 and 41 of frame 30. Proximal end 64 of shank 60
is bifurcated and encircles and is free to pivot about the bolt of
nut-and-bolt assembly 67 that extends through chamber 54 between side
plates 50 and 51 to permit shank 60 to pivot at proximal end 64 between
the lowered plowing position of tilling head assembly 61 and the elevated
clearance position of tilling head assembly 61.

[0031] Plow spring 70 is applied between frame 30 and shank 60 and acts
between and against frame 30 and shank 60 urging plow tool 32 toward the
lowered plowing position of tilling head assembly 61. Plow spring 70 is a
conventional aggressive tension spring that provides an outwardly bias
and consists of a wire formed into numerous active coils 71 including
two, opposed outermost coils 71A and 71B. Plow spring 70 is fashioned of
spring steel, a nickel-based spring alloy, or other material or
combination of materials having a substantially constant moduli of
elasticity as is typical with tension springs.

[0032] Referencing FIG. 10, an elongate bolt 80 has a bolt head 81 applied
to and against the outer or upper surface 52A of top plate 51, and an
elongate shaft or shank 82 that extends into chamber 54 through a central
opening 52B formed in top plate 52. Shaft 82 of bolt 80 extends
vertically downwardly through chamber 54 from upper end 40 of frame 30
toward lower end 41 of frame 30 along rear end 43 of frame 30 to a
threaded portion 83 threaded onto a bracket 85 located in chamber 54
between side plates 50 and 51. The underside of bracket 85 is formed with
a bifurcation 86 that receives a tongue 90 of an opposing shank bracket
91 located in chamber 54 between side plates 50 and 51, and which is
affixed to shank 60, such as by welding. Tongue 90 is pivoted to
bifurcation 86 with a nut-and-bolt assembly 93. The assembly consisting
of bolt 80 depending downwardly through chamber 54 from top plate 52 to
the bracket assembly consisting of pivotally attached brackets 85 and 91
is a plow spring support assembly, which is formed in chamber 54 along
rear end 43 of frame 30 between upper and lower ends 40 and 41 of frame
30 and which is free to move in reciprocal directions as generally
indicated by double arrowed line D in FIG. 10 between a lowered position
as shown in FIG. 10 defining the lowered plowing position of plow tool 32
and a raised position as shown in FIG. 10A defining the elevated
clearance position of plow tool 32. Shank 82 is free to reciprocate in
opening 52B of top plate 52 and there is sufficient clearance between
brackets 85 and 91 and side plates 50 and 51 of frame 30 to permit the
reciprocal movement of the plow spring support assembly during tripping
of plow tool 32 as discussed below.

[0033] Plow spring 70 is positioned in chamber 54 along rear end 43 of
frame 30 between upper and lower ends 40 and 41 of frame 30, and
encircles shank 82 between top plate 52 and bracket 85. Outermost coil
71A is an uppermost coil of plow spring 70 and is directed against the
underside or undersurface of top plate 52, outermost coil 71B is a lower
most coil of plow spring 70 and is directed against the upper side or
upper surface of bracket 85 opposite to bifurcation 86, and this provides
an operative coupling of plow spring 70 between top plate 52 of frame 30
and shank 60 of plow tool 32. Plow spring 70 aggressively acts between
top plate 52 of frame 30 and bracket 85 pivoted to shank bracket 91
affixed to shank 60 of plow tool 32 exerting a forcible bias against
shank 60 in a downward direction away from upper end 40 of frame 30 in a
direction indicated generally be arrowed line E urging plow tool 32
toward the lowered plowing position of tilling head assembly 61 as shown
in FIG. 4. Bolt 80 has a length extending from bolt head 81 to threaded
portion 83 threaded to bracket 85, and in the lowered plowing position of
plow tool 32 bolt head 81 is forced against upper surface 52A of top
plate 52, and the length of bolt 80 between bolt head 81 and threaded
portion 83 threaded to bracket 85 limits and stops the downward
displacement of plow tool 32 defining the lowered plowing position of
plow tool 32.

[0034] The installation and application of plow spring 70 between frame 30
and shank 60 of plow tool 32 is an automatic plow shank reset feature,
whereby spring 70 applies an initial preset force resisting movement of
shank 60 upwardly in the direction indicated by arrowed line E in FIG. 10
from the lowered plowing or field working position of plow tool 32. The
preset force is generated through a predetermined preload on plow spring
70. Once the preset force is overcome, such as when plow tool 32
encounters a bolder or other rigid object or obstacle, tripping occurs,
namely, shank 60 displaces upwardly in the direction indicated by arrowed
line F in FIG. 10 to a raised or elevated clearance position, as shown in
FIG. 12, to clear the obstruction compressing plow spring 70. When shank
60 displaces upwardly, brackets 91 and 85 are forced upwardly in chamber
54 toward upper end 40 of frame 30 driving bolt 80 upwardly through
opening 52B in top plate 52 compressing plow spring 70 in chamber 54
between top plate 52 and bracket 85 as shown in FIG. 10A. After the
obstruction is cleared, plow spring 70 decompresses forcing shank 60
downwardly back to the lowered plowing or field working position of plow
tool 32 as shown in FIG. 4. The pivotal coupling between bracket 85 and
opposed shank bracket 91 permit pivotal displacement therebetween as need
during tripping of plow tool 32.

[0035] The last main component of plow assembly 32 to be described is
runner 31. In the use of ground working apparatus 20, runner 31 supports
frame 30 at a fixed elevated location relative to the ground to be plowed
by tilling head assembly 61 of plow tool 32. Runner 31 is formed
preferably of steel, and is positioned between plow assembly 21 and
bridle assembly 22. Runner consists of an elongate, rigid member or
support 100 having an upper extremity or end 101 and an opposed lower
extremity or end 102 formed with an attached skid 103. Upper end 101 of
elongate member 100 is rigidly affixed directly to frame 30 and depends
downwardly from frame 30 to lower end 102 formed with skid 103, which is
positioned forwardly of plow tool 32 below frame 30, bridle assembly 22
and linkage assembly 24 as shown in FIGS. 4 and 5. As shown in FIGS. 4
and 5, skid 103 is located directly under linkage assembly 24 between
bridle assembly 22 and frame 30 ahead of tilling head assembly 61 of plow
tool 32.

[0036] Upper end 101 of elongate support 100 is rigidly affixed to side
plate 50 at side 44 of frame 30 proximate to rear end 43 of frame 30 with
nut-and-bolt assemblies 105 and 106. Upper end 101 extends downwardly
along the outer side of side plate 50 proximate to rear end 43 of frame
30, and elongate support 100 and depends downwardly from lower end 41 end
of frame 30 to lower end 102 formed with skid 103. As seen in FIG. 6
elongate support 100 not only depends downwardly from lower end 41 of
frame 30, elongate support 100 also angles inwardly under lower end 41 of
frame 30 from side 44 of frame 30 to lower end 102 to support and locate
skid 103 squarely under lower end 41 of frame 30 along the geometric
center of frame 30.

[0037] Plow assembly 21 is set upright in use, namely, plow assembly 21
extends upright from tilling head assembly 61 and skid 103 to frame 30,
and runner 31 and plow tool 32 depend downwardly from lower end 41 of
frame 30 to skid 103 and tilling head assembly 61, respectively to
concurrently run over and plow, respectively, ground to be plowed 26 as
shown in FIG. 4 along a plowing path B ahead of bridle assembly ground
working apparatus 20. Referencing FIG. 5, the lowermost portion of skid
103 of runner 31 resides along skidding or horizontal plane P1, the
lowermost portion of tilling head assembly 61 in the lowered plowing
position of tilling head assembly 61 resides along plowing or horizontal
plane P2 below plate P1, and there is a distance 108 defined between
plane P1 of skid 103 of runner 31 and plane P2 of tilling head assembly
61 of plow tool 32. Distance 108 between plane P1 and plane P2 is the
maximum plowing depth tilling head assembly 61 extends into ground to be
plowed 26 relative to skid 103 running over ground to be plowed 26, as
shown in FIG. 4. In the use of plow assembly 21, plow assembly 21 is
positioned upright, runner 31 runs over ground to be plowed 26 at skid
103 to maintain frame 30 at its fixed, predetermined height or elevation
relative to the ground to be plowed, and in the lowered plowing position
of plow tool 32 tilling head assembly 61 extends into ground to be plowed
26 at the depth defined by distance 108 relative to skid 103 running over
ground to be plowed 26 to plow into ground to be plowed 26 behind skid
103 to produce a furrow 110 in ground to be plowed 26 behind tilling head
assembly 61 as ground working apparatus 20 is drawn along plowing path B.
Not only does runner 31 set and support frame 30 at a fixed elevated
location relative to the ground to be plowed by tilling head assembly 61
of plow tool 32, it also sets the maximum depth of tilling head assembly
61 extends into ground to be plowed 26 in the lowered plowing position of
plow tool 32 at distance 108, in accordance with the principle of the
invention.

§C. The Bridle Assembly

[0038] Bridle assembly 22 secures plow frame 23 as shown in FIGS. 1 and 2,
and linkage assembly 24 couples plow assembly 21 to bridle assembly 22.
Referencing FIG. 3, bridle assembly 22 includes a bridle coupling 120,
and two U-bolt assemblies including U-bolts 150 and corresponding nuts
151. Bridle coupling 120 includes a bridle coupling 120 preferably formed
of steel and which includes a face plate 121, having opposed upper and
lower extremities 122 and 123, coupled between and rigidly connecting,
preferably by welding, opposed, spaced-apart, parallel bracket plates 130
and 140, which are identical in size and shape. Bracket plates 130 and
140 have upper ends 131 and 141 and opposed lower ends 132 and 142, front
ends 133 and 143, and opposed rear ends 134 and 144, and intermediate
sockets 135 and 145, respectively. Socket 135 is formed between upper and
lower ends 131 and 132 of bracket plate 130, and extends into bracket
plate 130 from front end 133 toward rear end 134. Socket 145 is formed
between upper and lower ends 141 and 142 of bracket plate 140, and
extends into bracket plate 140 from front end 143 toward rear end 144.
Sockets 135 and 145 are identical in size and shape and relate to the
segment of plow frame 23.

[0039] Segment 23' of plow frame 23 has opposed inner and outer sides 23A
and 23B as referenced in FIG. 3. Bridle coupling 120 is positioned along
outer side 23B of segment 23' and is applied over segment 23' in a
direction toward outer side 23B, in which segment 23' is inserted into
and received by sockets 135 and 145 of bridle coupling 120 locating face
plate 121 along outer side 23B of the segment of plow frame 23. With
bridle coupling 120 so applied to the segment of plow frame 23, face
plate 121 extends vertically upward along outer side 23B of segment 23'
from lower extremity 123 positioned below segment 23' to upper extremity
12 positioned above segment 23', and bracket plates 130 and 140 straddle
segment 23' and, like face plate 121, extend vertically upward along
outer side 23B of the segment of plow frame 23 from lower ends 132 and
142, respectively, positioned below segment 23' to upper ends 131 and
141, respectively, positioned above segment 23'. To secure bridle
coupling 120 in place, U-bolts 150 are applied over segment 23' in a
direction toward outer side 23B between bridle plates 130 and 140
straddling segment 23' and the threaded ends of U-bolts 150 are applied
through corresponding openings formed in face plate 121. Nuts 151 are
threaded onto the threaded ends of U-bolts 150 and are tightened securing
bridle coupling 120 to segment 23' and firmly and securely clamping
segment 23' by and between bridle coupling 120 and the U-bolt assemblies.
Having applied and secured bridle assembly 22 to segment 23' of plow
frame 23, linkage assembly 24 is coupled between plow assembly 21 and
bridle assembly 22 coupling plow assembly 21 to bridle assembly 22 as
shown in FIGS. 1, 2, 4, 5, 11, and 12.

§D. The Linkage Assembly

[0040] Linkage assembly 24 couples plow assembly 21 located rearwardly of
or otherwise downstream of inner side 23A of segment 23' to bridle
assembly 22 secured to segment 23' of plow frame 23 ahead of plow
assembly 21. Segment 23' is located substantially between plow assembly
21 and bridle assembly 22 as shown in the various drawings, particularly
FIGS. 4, 5, 11 and 12. Linkage assembly 24 couples frame 30 to bridle
assembly 22 to secure a plow frame 23 for movement or displacement of
plow assembly 21 in reciprocal directions generally indicated by double
arrowed line A in FIGS. 4, 5 and 11 between a lowered position of plow
assembly 21 with respect to bridle assembly 22 as shown in FIGS. 4 and 5
and segment 23' of plow frame 23 that bridle assembly 22 secures, and a
raised position of plow assembly with respect to bridle assembly 22 as
shown in FIG. 11 and segment 23' of plow frame 23 that bridle assembly 22
secures.

[0041] Referencing FIG. 3, and referencing in relevant part FIGS. 1, 2, 4,
and 5, linkage assembly 24 consists of generally horizontal upper and
lower links 160 and 180 pivoted to frame 30 of plow assembly 21 and to
bridle coupling 120 of bridle assembly 120. Upper link 160 extends
between frame 30 and bridle coupling 120 and is located above segment 23'
or otherwise above the upper side of segment 23', and lower link 180
opposes upper link 160 and extends between frame 30 and bridle coupling
120 and is located below segment 23' or otherwise below the lower side of
segment 23'. Upper and lower links 160 and 180 are pivoted to frame 30 at
frame pivot points, and upper and lower links 160 and 180 are pivoted to
bridle coupling 120 of bridle assembly 22 at bridle pivot points. The
frame pivot points between upper and lower links 160 and 180 and frame 30
are located on either side of the pivot point between proximal end 64 of
shank 60 and frame 30 defined at nut-and-bolt assembly 67, and the bridle
pivot points between upper and lower links 160 and 180 and bridle
coupling 120 are located at upper ends 131 and 141 and lower ends 132 and
142 of bridle plates 130 and 140. More particularly, the frame pivot
point between upper link 160 and frame 30 is located near front end 42 of
frame 30 between upper end 40 of frame 30 and the pivot point between
proximal end 64 of shank 60 and frame 30 and also somewhat rearwardly of
the pivot point between proximal end 64 of shank 60 and frame 30, and the
frame pivot point between lower link 180 and frame 30 is located at lower
end 41 of frame 30 under and somewhat rearwardly of the pivot point
between proximal end 64 of shank 60 and frame 30.

[0042] Upper link 160 is an assembly consisting of opposed, parallel,
coextensive upper bars or link members 161 and 166 rigidly connected by
an intermediate strut 165. Link member 161 has opposed inner and outer
ends 162 and 163, and link member 166 has opposed inner and outer ends
167 and 168. Inner end ends 162 and 167 of link members 161 and 166 are
applied exteriorly of frame 30 along sides 44 and 45 of frame 30 and are
pivoted to side plates 50 and 51 of frame 30 at the frame 30 pivot points
with nut-and-bolt assemblies 170 and 171. Link members 161 and 166
project forwardly of the frame pivot points defined by nut-and-bolt
assemblies 170 and 171 to outer ends 163 and 168, which are applied along
upper ends 131 and 141, respectively, of bracket plates 130 and 140.
Outer ends 163 and 168 are pivoted to upper ends 131 and 141,
respectively, of bracket plates 130 and 140 with corresponding
nut-and-bolt assemblies 175 and 176.

[0043] Lower link 180 is, like upper link 160, an assembly consisting of
opposed, parallel, coextensive lower bars or link members 181 and 186
rigidly connected by an intermediate strut 185. Link member 181 has
opposed inner and outer ends 182 and 183, and link member 186 has opposed
inner and outer ends 187 and 188. Inner end ends 182 and 187 of link
members 181 and 186 are applied exteriorly of frame 30 along sides 44 and
45 of frame 30 and are pivoted to side plates 50 and 51 of frame 30 at
the frame 30 pivot points with nut-and-bolt assemblies 190 and 191. Link
members 181 and 186 project forwardly of the frame pivot points defined
by nut-and-bolt assemblies 170 and 171 to outer ends 183 and 188, which
extend along and past lower ends 132 and 142, respectively, of bracket
plates 130 and 140. Link members 181 and 186 are pivoted to lower ends
132 and 142, respectively, of bracket plates 130 and 140 at the bridle
pivot points with corresponding nut-and-bolt assemblies 195 and 196. The
bridle pivot points defined by nut-and-bolt assemblies 195 and 196
applied between link members 181 and 186 and lower ends 132 and 142 of
bracket plates 130 and 140, respectively, are located at a generally
intermediate position with respect to inner ends 182 and 183 and outer
ends 187 and 188 of link members 181 and 186, respectively, inboard of
outer ends 183 and 188, which forms in link members 182 and 186
extensions 183' and 188', respectively, projecting forwardly of not only
of the bridle pivot points between link members 181 and 186 and lower
ends 132 and 142 of bridle plates 130 and 140 to outer ends 183 and 188
of link members 181 and 186, but also of bridle assembly 22 and plow
assembly 21. Extensions 183' and 188' cooperate to form and define an
extension of lower link 180.

[0044] Accordingly, upper link 160 consists of a pair of opposed,
connected, upper bars or link members 161 and 166 pivoted between frame
30 of plow assembly 21 and upper ends 131 and 141 of bridle coupling 120
of bridle assembly 22, and lower link 180 consists of a pair of opposed,
connected, lower bars or link members 181 and 186 pivoted between frame
30 of plow assembly 21 and lower ends 132 and 142 of bridle coupling 120
of bridle assembly 22, and this arrangement permits plow frame 21 to move
or otherwise displace in reciprocal directions generally indicated by
double arrowed line A in FIGS. 4, 5 and 11 between the lowered position
of plow assembly 21 with respect to bridle assembly 22 as shown in FIGS.
4 and 5, and the raised position of plow assembly with respect to bridle
assembly 22 as shown in FIG. 11. As linkage assembly 24 incorporates
opposed pairs of upper and lower bars or link members, linkage 24 is
exemplary of four-bar linkage, which is highly reliable and stable.

§E. Load Take-Up Assembly

[0045] Plow assembly 21 defines a weight or load, and ground working
apparatus 20 incorporates a load take-up assembly coupled between bridle
assembly 22 and linkage assembly 24 that applies a bias to linkage
assembly 24 urging plow assembly 21 toward its raised position away from
its the lowered position partially taking up the load of plow assembly
21. Referencing FIG. 3, this load take-up assembly consists of a bridle
spring 210 coupled between bridle coupling 120 of bridle assembly 22 and
the extension of lower link 180. Bridle spring 210 acts between bridle
coupling 120 and the extension of lower link 180 and applies a bias
across linkage assembly 24 urging plow assembly 21 toward its raised
position away from its lowered position.

[0046] With continuing reference to FIG. 3, and referencing in relevant
part FIGS. 1, 2, 4-6, and 8, a bracket plate 200 is affixed to upper
extremity 121 of face plate 121, which extends upward and forwardly
therefrom away linkage assembly 24 and plow assembly 21. Bracket plate
200 is part of and also an extension of face plate 121, and is spaced
above and is located opposite to the extension of lower link 180 formed
by extensions 183' and 188' of lower link members 181 and 186. A bridle
spring 210 is coupled between bracket plate 200 of bridle coupling 120
and the extension of lower link 180 formed by extensions 183' and 188',
and imparts a forcible outward bias between bracket plate 210 and the
extension of lower link 180 formed by extensions 183' and 188' pushing or
otherwise biasing the extension of lower link 180 downwardly in the
direction indicated by arrowed line G in FIGS. 4 and 5. This applied bias
to the extension of lower link 180 imparts across linkage assembly 24 a
corresponding bias which urges plow assembly 21 toward its raised
position away from its the lowered position in the direction indicated by
arrowed line H in FIGS. 4 and 5, in accordance with the principle of the
invention, taking up a part of the load of plow assembly 21.

[0047] Bridle spring 210 is a conventional aggressive tension spring
consisting of a wire formed into numerous active coils 211 including two,
opposed outermost coils 211A and 211B. Outermost coil 211A is considered
an uppermost coil of bridle spring 210, and outermost coil 211B is
considered a lowermost coil of bridle spring 210. Bridle spring 210 is
fashioned of spring steel, a nickel-based spring alloy, or other material
or combination of materials having a substantially constant moduli of
elasticity as is typical with tension springs. Bridle spring 210 is
smaller and less aggressive compared to plow spring 70.

[0048] A central opening 200A (FIG. 3) is formed in bracket plate 200.
Opening 200A accepts a pin 220 affixed to a rounded bearing 221, which
depends downwardly from bracket plate 200 and which is positioned between
bracket plate 200 and the extension of lower link 180. As best
illustrated in FIGS. 3 and 8, rounded bearing 221 is applied into
outermost coil 210A, and bridle spring 210 extends vertically downwardly
therefrom to outermost coil 210B, which is affixed, such as by welding,
to a bracket 223 coupled to the extension of lower link 180 formed by
extensions 183' and 188'. The underside of bracket 223 is formed with a
bifurcation 224 positioned between extensions 183' and 188'. Bifurcation
224 is received about a bolt of nut-and-bolt assembly 225 applied between
and secured to extensions 183' and 188'. Nut-and-bolt assembly 225
applied between and secured to extensions 183' and 188' is considered
part, of or otherwise an extension of, the extension of lower link 180.
Bracket 223 affixed to outermost coil 211B and which is formed with
bifurcation 224 received about the bolt of nut-and-bolt assembly 225
applied to and between extensions 183' and 188' cooperate to form a
coupling between outermost coil 211B of bridle spring 211 and the
extension of lower link 180. Bifurcation 224 is free to pivotally
displace about the bolt of nut-and-bolt assembly 225, and rounded bearing
221 and outermost coil 211A are also free to pivotally displace with
respect to each other. Bracket plate 200 and rounded bearing 221 carried
by pin 220 applied to bracket plate 200 cooperate to form a bracket
between bridle coupling 120 of bridle assembly 22 and outermost coil 211A
of bridle spring 210, and bridle spring 210 is captured by and between
this described bracket and the extension of lower link 180 of link
assembly 24.

[0049] The installation and application of bridle spring 210 between
bridle assembly 22 and the extension of lower link 180 formed by lower
link members 181 and 186 is an automatic plow assembly load take-up and
plow assembly 21 reset feature, whereby bridle spring 210 applies an
initial preset force across linkage assembly 24 at the extension of lower
link 180 of linkage assembly 24 urging plow assembly 21 upwardly in the
direction indicated by arrowed line H in FIGS. 4 and 5, which, while
insufficient to alone displace plow assembly 21, takes up a portion of
the load of plow assembly 21, such as approximately 30 percent of the
load of plow assembly 21. The preset force is generated through a
predetermined preload on bridle spring 210. As a matter of example, when
skid 103 of runner 31 encounters an obstacle, such as a rock or other
obstacle on the ground over which skid 103 of runner 31 is being drawn in
the use of ground working apparatus 20, the preset load of bridle spring
210 applying the described bias to plow assembly 21 allows plow assembly
21 to more easily displace upwardly in the direction indicated by arrowed
line H in FIGS. 4 and 5 in response to skid 103 of runner 31 encountering
an obstacle. When plow assembly 21 displaces upwardly, the extension of
lower link 180 pivotally moves away from rounded bearing 221 increasing
the distance between the extension of lower link 180 and rounded bearing
221 decompressing bridle spring 210 therebetween releasing the tension
applied across bridle spring 210. After the obstruction is cleared, plow
assembly 21 displaces downwardly toward the ground to be plowed until
skid 103 encounters the surface of the ground to be plowed resetting
frame 30 of plow assembly 21 at is fixed elevated location above and
relative to the ground to be plowed. When plow assembly 21 displaces
downwardly, the extension of lower link 180 pivotally moves toward
rounded bearing 221 decreasing the distance between the extension of
lower link 180 and rounded bearing 221 compressing bridle spring 210
therebetween increasing the tension applied across bridle spring 210
dampening the movement of plow assembly 21 from its raised position back
to its lowered position preventing plow assembly 21 from slamming against
the ground to be plowed, which could otherwise damage plow assembly 21 or
compromise the linkage between plow assembly 21 and bridle assembly 22.
The pivotal coupling between outermost coil 211A and rounded bearing 221
and the pivotal coupling between bracket 223 and nut-and-bolt assembly
225 coupled to extensions 183' and 188', which forms part of the
extension of lower link 180, permits any required pivotal displacement
between bridle spring 210 and bridle assembly 22 during the compression
and decompression of bridle spring 210 in response to the upward and
downward displacement of plow assembly 21 relative to bridle assembly 22
and the ground to be plowed.

§F. Operation of the Ground Working Apparatus

[0050] In operation, bridle assembly 22 is secured to segment 23' of plow
frame, plow assembly 21 is positioned rearwardly of segment 23' of plow
frame 23, and linkage assembly 24 is formed between plow assembly 21 and
bridle assembly 22 and pivotally couples frame 30 and bridle coupling 120
of bridle assembly 22. Plow assembly 21 is positioned upright behind
segment 23' of plow frame 23. Runner 31 and plow tool 32 depend
downwardly from frame 30 to concurrently run over and plow, respectively,
ground to be plowed 26 as illustrated in FIG. 4 as ground working
apparatus 20 is moved along plowing path B ahead of ground working
apparatus 20. Runner 31 depends downwardly from frame 30 to skid 103 that
runs over ground to be plowed 26, and plow tool 32 depends downwardly
from frame 30 to plow ground to be plowed 26. Skid 103 of runner 31
positioned between plow assembly 21 and bridle assembly 22 runs over
ground to be plowed 26, such that runner 31 thereby sets frame 30 of plow
assembly 21 at a fixed elevated position with respect to ground to be
plowed 26 as ground working apparatus 20 is moved and applied along
plowing path B denoted in FIG. 4 in a direction leading with bridle
assembly 22 and trailing with plow assembly 21. The application of runner
31 between frame 30 and ground to be plowed sets frame 30 at a fixed
elevated height or location above ground to be plowed 26, and also sets
the plowing depth of plow tool 32 in ground to be plowed at distance or
depth 108 as measured between plane P1 of skid 103 running along the
surface of ground to be plowed and plane P2 of tilling head assembly 61
of plow tool 32 extending into ground to be plowed 26, in accordance with
the principle of the invention.

[0051] Plow tool 32 is, of course, mounted to frame 30 for movement in
reciprocal directions as generally indicated by the double arrowed line C
in FIGS. 4 and 12 between the lowered plowing position of tilling head
assembly 61 as shown in FIG. 4 to extend into and plow ground to be
plowed 26, and the elevated clearance position of tilling head assembly
61 as shown in FIG. 12 to clear an impacting obstacle. Plow spring 70
applied between frame 30 and shank 60 of plow tool 32 acts therebetween
and biases or otherwise urges plow tool 32 into the lowered plowing
position of tilling head assembly 61. The installation and application of
plow spring 70 between frame 30 and shank 60 of plow tool 32 is an
automatic plow shank reset feature as described. Namely, plow spring 70
applies an initial preset force resisting movement of shank 60 upwardly
in the direction indicated by arrowed line E in FIG. 10 from the lowered
plowing or field working position of plow tool 32 to maintain tilling
head assembly 61 in the lowered plowing or field working position. When
the preset force is overcome, such as when plow tool 32 encounters an
obstacle, such as when tilling head assembly 61 encounters a rock,
boulder, or other obstacle in ground to be plowed 26, tripping occurs,
whereby shank 60 displaces upwardly in the direction indicated by arrowed
line F in FIG. 10 to a raised or elevated clearance position, as shown in
FIG. 12, to allow plow tool 32 to clear the obstruction. After the
obstruction is cleared, plow spring 70 forces forcing plow tool 32
downwardly at shank 60 back to the lowered plowing or field working
position of plow tool 32 as shown in FIG. 4. It is to be emphasized that
the length of bolt 80 between bolt head 81 applied to top plate 52 of
frame and threaded portion 83 threaded to bracket 85 limits and stops the
downward displacement of plow tool 32 and defines the lowered plowing
position of plow tool 32, namely, the lowered plowing or field working
position of tilling head assembly 61 of plow tool 32.

[0052] Linkage assembly 24 couples frame 30 to bridle assembly 22 for
movement or displacement of plow assembly 21 in reciprocal directions
generally indicated by double arrowed line A in FIGS. 4, 5 and 11 between
a lowered position of plow assembly 21 with respect to bridle assembly 22
as shown in FIGS. 4 and 5, and a raised position of plow assembly with
respect to bridle assembly 22 as shown in FIG. 11. As ground working
apparatus 20 is drawing along the plowing path B, linkage assembly 24
permits plow assembly 21 to reciprocate and displace between its raised
and lowered positions relative to bridle assembly 22 and segment 23' of
plow frame 23 to ensure plow assembly 21 remains operational as it is
drawn along plowing path B, namely, to ensure runner 31 and plow assembly
32 concurrently run over and plow, respectively, ground to be plowed 26
as shown in FIG. 4.

[0053] The installation and application of bridle spring 210 between
bridle assembly 22 and the extension of lower link 180 formed by lower
link members 181 and 186 is an automatic plow assembly load take-up and
plow assembly 21 reset feature as described, in which bridle spring 210
acts between bridle assembly 22 and the extension of lower link 180
applying a bias across linkage assembly 24 at the extension of lower link
180 of linkage assembly 24 urging plow assembly 21 upwardly in the
direction indicated by arrowed line H in FIGS. 4 and 5, which is
insufficient to displace plow assembly 21 but takes up a portion of the
load of plow assembly 21. And so when skid 103 of runner 31 encounters an
obstacle, such as a rock or other obstacle on the ground over which skid
103 of runner 31 is being drawn in the use of ground working apparatus
20, the preset load of bridle spring 210 applying the described bias to
plow assembly 21 allows plow assembly 21 to readily displace upwardly in
the direction indicated by arrowed line H in FIGS. 4 and 5 in response to
skid 103 of runner 31 encountering an obstacle. After an obstruction is
cleared, plow assembly 21 is free to displace downwardly toward the
ground to be plowed until skid 103 encounters the surface of the ground
to be plowed resetting frame 30 of plow assembly 21 at is fixed elevated
location above and relative to the ground to be plowed. Because bridle
spring 210 is insufficient to displace plow assembly 21 and takes up only
a portion of the load of plow assembly 21, when an obstacle is cleared,
bridle spring 210 does not restrict plow assembly 21 from moving back to
its lowered plowing position, but rather dampens the downwardly movement
of plow assembly 21 causing plow assembly 21 to gently descend from its
raised position and back to its lowered position to allow runner 31 and
plow assembly 32 concurrently run over and plow, respectively, ground to
be plowed 26 as shown in FIG. 4. This dampening of plow assembly 21
through the application of bridle spring 210 dampens movement of plow
assembly 21 from its raised position back to its lowered position
preventing plow assembly from slamming against the ground to be plowed,
which could otherwise damage plow assembly 21 or compromise the linkage
between plow assembly 21 and bridle assembly 22.

[0054] The present invention is described above with reference to a
preferred embodiment. However, those skilled in the art will recognize
that changes and modifications may be made in the described embodiment
without departing from the nature and scope of the present invention. For
instance, in the preferred embodiment of ground working apparatus 20 plow
spring 70 is a compression spring, which acts between and against frame
30 and shank 60 urging plow tool 32 toward the lowered plowing position
of tilling head assembly 61. Also, bridle spring 210 is a compression
spring, which acts between bridle coupling 120 and the extension of lower
link 180 and applies a bias across linkage assembly 24 urging plow
assembly 21 toward its raised position away from its lowered position.
The compression springs forming the preferred embodiments if plow spring
70 and bridle spring 210 can, in alternate embodiments, each include a
plurality of compression springs, one or more inflated bladders, or other
instrument, apparatus, or device suitable to impart the applied biases.
Furthermore, runner 31 runs over ground to be plowed 26 at skid 103 to
maintain frame 30 at its fixed position. In a further embodiment, skid
103 can incorporate or be replaced with one or more wheels to provided
wheel movement of runner 31 over the ground to be plowed.

[0055] Various further changes and modifications to the embodiment herein
chosen for purposes of illustration will readily occur to those skilled
in the art. To the extent that such modifications and variations do not
depart from the spirit of the invention, they are intended to be included
within the scope thereof.

[0056] Having fully described the invention in such clear and concise
terms as to enable those skilled in the art to understand and practice
the same, the invention claimed is: